Railway block-signaling system.



H. M. GOULTER. RAILWAY BLOCK SIGNALING SYSTEM.

Patented Nov. 17, 1908.

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APPLIUATION FILED APR. 8, 1907.

n4: NORRIS PETERS cm, WASHINGTON, n. c.

H. M. GOULTER. RAILWAY BLOGK SIGNALING SYSTEM. APPLICATION rum) APR. 8,1907.

904,1 1 6. Patented Nov. 17, 1908.

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L1 N i f H. M. GOULTER.

RAILWAY-BLOCK SIGNALING SYSTEM.

Patented Nov. 17, 1908.

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I f6 77 Gay/Zia)" UNITED STATES PATENT OFFICE.

HARRY M. GOULTER, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO ALFREDSTROMBERG, OF CHICAGO, ILLINOIS.

RAILWAY BLOCK-SIGNALING SYSTEM.

To all whom it may concern:

Be it known that I, HARRY M. COULTER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Railway Block-SignalingSystems, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification.

The invention upon which I desire to se cure Letters Patent is ingeneral an improvement upon the railway block signaling system describedand claimed in United States Letters Patent No. 794,784.- granted to meon July 18th, 1905.

The improvements which constitute my present invention are directedtoward the simplification and increased efficiency of the system setforth in my earlier patent.

The system of the present application dispenses with the need of groundreturn circuits; it eliminates many of the sources of current supplywhich are shown in my earlier application; it provides means formaintaining the display or actuation of the cab signals until they arerestored to their normal condition by a positive act upon the part of atrainman; the form of stationary and moving track contacts is improved,and the circuits are improved in various respects which will more fullyappear from the following detailed description.

I have illustrated in Figure 1 of the accompanying drawings the trackand signaling circuits of my invention; Fig. 2 illustrates the circuitsand mechanism placed upon a locomotive and adapted to cooperate with thesignaling circuit shown in Fig. 1; Fig. 3 illustrates a modification ofthe track and controlling relay circuits; Fig. 4 shows diagrammaticallythe placement of the moving contacts upon the engine tender; Fig. 5shows in side elevation the track contacts and their supports, and Fig.6 is an enlarged view of one of the track contacts.

As an aid in understanding the circuit drawings, it may be said at theoutset that the preferred embodiment of my invention comprises asignaling device carried by and upon a locomotive, these devicesresponding to the flow of electrical currents. hen a current of onestrength flows through the Patented Nov. 17, 1908.

Serial No. 366,924.

rents of differing strength flow. through the set of apparatus. videdinto a series of blocks. contacts are placed along the side of eachblock of the track in such a manner as to make electrical connectionwith cooperating contacts carried by the locomotive. The track andsignal controlling circuits cooperate to establish circuits leading fromthe track contacts, the character of the circuit leading from any set oftrack contacts corresponding with the condition of traflic in the nearbyblocks of the track. Each block of the track is equipped with a trackcircuit which includes the winding of a controlling relay. Thecontrolling relays determine the character, as, for example, the amountof re sistance in the circuits leading from the track contacts situatedin the neighboring blocks.

With this preliminary explanation and reference to Fig. 1, it will beunderstood that the series of blocks lettered A, B, C, D and E are eachequipped with a source of current, as, for example, a battery of gravitycells 11, 11. One of these gravity batteries is connected in bridgeacross the two rails at one end of each block. Near the other end ofeach block the controlling relays are connected with the two rails asshown. These cont-rolling relays are designated by the nu meral 13 towhich a letter corresponding with the associated block is appended. Itwill be seen that current flows normally from the positive pole of thetrack battery through one rail from one end of the block to the other,thence through the winding of the associated controlling relay, (theserelays being lettered 13 13, 13, etc), and back through the other trackof the pair and thence to the negative pole of the track battery. Thecontrolling relays are, therefore, normally energized and maintain theirarmatures in the attracted position shown in Fig. 1 of the drawings.

If through any accident one of the rails of a given block becomesbroken, the electrical circuit through the associated controlling relayis opened, and the interruption in the flow of current causes the relayarmatures to fall back to their abnormal position. So also the presenceof a car truck on the two rails of any one block causes the winding ofthe associated controlling relay to be short-circuited on account of thelow resistance of the circuit afforded through the The railroad track isdi- Suitable track wheels and car axles, and this condition also willcause the controlling relay to be deenergized.

Before attempting to trace the signaling circuits, it may be well tostate that Fig. 1 shows a single track railroad equipped with circuitsfor block signaling in both directions,that is to say, the presence of acar truck as indicated in dotted lines in block C, will cause thedisplay of suitable signals in both directions. The track contacts atthe far side of the track, as shown in Fig. 1, are used in signalingtrains coming from the right, While the contacts shown at the near sideof the track are used in signaling a train coming from the left. Thetrack contacts for each block are located in pairs and form theterminals of circuits in which suitable resistances are connected. Thesignal controlling relays determine the resistance in each of thesignaling circuits in a manner depending upon the condition of thetrafiic in the associated block. The drawing shows each block equippedwith three pairs of track contacts on either side of the track andlettered respectively to correspond with the designation of the blockitself. Thus the outgoing contacts of block E at the far side of thetrack are lettered e, 6, while the return contacts are lettered e 6 Onthe near side of the track the out-going contacts for block E arelettered e 6 while the return contacts are lettered e 6 I havedesignated the various parts which are directly associated with eachcontrolling relay with a numeral to which is subjoined a lettercorresponding with the designation of the block whose track circuitcontrols the operation of the controlling relay. Thus the armatures ofthe controlling relay are lettered respectively 14 and 15, 14 and 15,etc. The front contacts with which the armatures numbered 15 normallymake connection, each bear the numeral 16. The associated back contactsare numbered 17. Each of the armatures bearing the number 14 is providedwith two back contacts munbered respectively 18 and 19. Connected withthe armatures 15 I have shown resistances numbered 20 and 21 Whileanother resistance 22 is connected in a circuit between the frontcontact 16 and the common return wire R.

Each pair of track contacts constitute under normal conditions theterminals of a high resistance circuit,for example, a circuit may betraced from any one of the track contacts 6 through the wire which leadsby way of the resistance 20 to the armature 15, thence through the frontcontact 16 and the resistance 22 to the common return wire R and thenceback through the wire e to the return track contact 6 It will be notedthat this circuit contains two resistance coils, the resistance of whichmay be made alike or different and of an alnoi'lnt appropriate to theactuation of the instrumentalities hereinafter to be described.

If due to a break in the track circuit of the block C or due to thepresence of a truck upon the track in block C the controlling relay 13becomes deenergized, then the armatures 14 and 15 will fall back intothe abnormal positions indicated by the dotted lines. Such adeenergization of the controlling relay reduces the resistance of thecircuit just traced as will be made apparent by following the circuitfrom the track contacts e by way of the resistance 20 to the armature15, thence by way of the back contact 17, the common return wire R andthe return wire 6" to the return contacts 6 This circuit now containsonly one resistance, namely, that lettered 20. Thus, it will be seenthat the presence of a truck in the block C changes the signalingcircuit which terminates in the contacts 0, c from its normal conditioninto a condition in which the resistance of this circuit is reduced.

Since the locomotive is equipped with instrumentalities differentiallyaffected by the resistance of the circuit terminating in the trackcontacts, it will be apparent that a locomotive when coming from theright and reaching block E may receive a signal to indicate that thereis an obstruction or a break in the second block in advance,-that is,block C.

If the train approaching from the right enters block D and establishesconnection through the track contacts d, al it will find a circuit inwhich both resistances have been cut out. This will be made apparent bytracing the circuit from the contacts cl through the wire leading to thecontact 19 and thence through the armature 14, the armature 15, the backcontact 17, the common return wire R and the return wire cl to the trackcontact al The instrumentalities on the locomotive are adapted torespond differentially to this second reduction in the resistance of thesignaling circuit, providing the engineer with. a distinctive signal toapprise him of the fact that there is an obstruction or break in thenext succeeding block.

It will be unnecessary to trace these circuits for each of the blocks,for they are in all respects duplicated over and over again for each ofthe blocks of the system. The circuits are such that under normalconditions the controlling relay for each block establishes a circuit ofhigh resistance terminating in the track contacts two blocks distant.Upon the deenergization of any controlling relay, the track contacts twoblocks distant are provided with a circuit of decreased resistance,while the track contacts in the next adjoining block are provided with acircuit of still lower resistance.

When, as shown in Fig. 1, a single track is wire a to the track contactsa provided with the block signaling circuits in order to signal trainsrunning in both directions, the track contacts a and a b and 79 etc.,are likewise made the terminals of circuits whose resistance iscontrolled by the controlling relays numbered 13. Thus, for example,under normal conditions, a circuit may be traced from the track contactsa through the wire leading by way of the resistance 21 to the armature15 and thence through the contact 16, the resistance 22, the commonreturn wire R and the return This circuit, it will be noted contains thetwo resistances 21 and 22. WVhen the presence of a car or train on thetrack which constitutes block C causes a deenergization of thecontrolling relay. 13, one of these two resistances is cut out of thesignaling circuit which leads from the track terminals at the near sideof block A, for upon tracing the circuit from the contacts a it will beseen that current has now to flow only through the resistance 21, thearmature 143, the back contact 17 the common return wire R and thereturn wire a in order to reach the contacts a If, therefore, a train isstanding or moving in block C, any other train approaching from the leftand making electrical connection with the contacts a a will be providedwith a signaling circuit of lower resistance than would be the case ifblock C were clear. The train approaching from the left may proceedunder reduced speed into the block D, where if the train or obstructionhas not been removed from the block C, a signaling circuit of stilllower resistance will be provided for actuation of the signaling devicelocated upon the moving train. This will be made apparent by tracing thepath of current from the track contacts Z1 through the wire which leadsto the back contact 18 and thence through the armature 14, the armature15 contact 17 the common return wire R and the return wire Z) to thetrack contacts 6 In this last signaling circuit there are no specialresistances whatever. It will be seen, there fore, that my inventionprovides signaling circuits and electromagnetic mechanism, such that thepresence of a truck in any block or a break of the track in any blockwill cause a certain reduction in the resistance of signaling circuitsrunning in both directions and terminating in track contacts two blocksdistant, while at the same time the deenergization of the signalcontrolling relay will establish circuits of still lower resistanceterminating in the track contacts of the next block in both directions.

I have already referred-to the fact that the instrumentalities carriedupon the moving locomotive are adapted to respond differentially inaccordance with the condition of the signaling circuit terminating inthe track contacts with which the locomotive circuit makes electricalconnection. The 10- comotive circuit and apparatus is shown diagrammatically in Fig. 2. It consists essentally of three signal relays,each numbered 25 and provided respectively with indices t, is and .9corresponding with the respective purposes of the signal relays, thefirst of which controls the test signal, the second, the caution signal,and the third, the stop signal. The corresponding parts of these threerelays are similarly numbered, but in each case provided with an indexcorresponding with the function of the relay with which it isassociated. Each relay is provided with an armature numbered 26 adaptedupon attraction to make connection with the associated front contact 27.Each relay armature controls an electrical circuit through an associatedsignal lamp 28 and a signal bell 29. The test lamp may conveniently havea globe of one color,-for example, white, while the caution lamp andfull stop lamp may be colored blue and red respectively. In like mannerthe signal bells may be provided with gongs of different tones or may bemade to ring in charac teristically different ways.

As indicated in the dra ring, the retracting springs of the three signalrelays are placed under different tensions in order to make the relaydifferentially responsive to currents of difiering strength. This difference in the adjustment of the relays may be augmented by providing themwith windings of different resistances and numbers of turns. Theadjustment is such that the flow of a small current through all of therelay windings will energize the relay 25 sufficiently to cause theattraction of the armature 26; but the armatures 26 and 26 will not beattracted. It is, in fact, preferable to make the adjustment of thecaution and full stop relays such that their armatures will not beretained in the attracted position even though they be brought into suchposition during the flow of current suiiicient to cause the attractionof the armature of the test relay 25K in a similar manner the adjustmentof the full stop relay '25 is made such that it will notbe actuated by acurrent of intermediate strength which is, how .ver, strong enough tocause the actuation of the caution relay 25 It is only tee flow of acurrent of maximum strength which will suflice to actuate the armatureof the full stop relay.

With this explanation it will be readily understood how the locomotivecircuit cooperates with the signaling circuits of Fig. 1 to furnish theengineer with signals by means of which he may determine the conditionof the track either one or two blocks ahead. A suitable source ofcurrent, as, forin circuit with the main windings oi the signal relays,the terminals of this circuit being in the form of contact rails G and Hwhich are mechanically attached to but electrically insulated from thetender of the engine, as best illustrated in Fig. 4. These contact ailsare placed at such a height and in such position that they will registerwith the pairs of track contacts 0 and 0 (Z and (Z etc., while thelocomotive is passing such contacts. The pairs of track contacts mayconveniently be located a quarter of a mile apart, and if the blocks area mile long, there will be four or five pairs of track contacts to ablock. II" we consider a train approaching from the right and reachingolock E under normal conditions, the moving contacts G and H will makeelectrical connections respectively with the track con tacts e and 6 Itwill be remembered that under normal conditions the signaling circuitterminating in these track contacts was one containing two specialresistances 20 and 22". It will be only a limited current which thestorage battery L will be able to force through this signaling circuitand the main windings of the signal relays 25. The adjustments are madesuch, however, that this small current will cause the attraction of thearmature of the test relay, causing the momentary illumination of thetest lamp 2S and a stroke of the test bell 29, the current for theoperation of these signaling devices being supplied through anappropriate circuit from the local battery M. The current which thebattery L forces through this normal signaling circuit of highresistance is, however, insufficient to cause the actuation of thearmatures of either the caution or the full stop signal relays. Theengineer is, therefore, provided with a test signal which is repeatedfour or live times, or as shown in the drawings, three times during thepassage of each block. If there is a train or a broken rail in block C,when the approaching train reaches block E there will be a correspondingchange in the resistance of the signaling circuit which terminates inthe track contacts 6, 6 due to the deenergization of the controllingrelay 13, as previously explained. The deenergizati on of this relayserving, as it does, to cut out part of the resistance in the signalingcircuit which terminates in block E, the connection of the contact railsG and H with the track contacts 0 and 0 will cause the flow of a currentof intermediate strength through the main windings of the signal relayslocated upon the moving train. This current, as previously explained,will be sufficient to actuate not only the test relay 25 but also thecaution relay 25. The adjustments are made such, however, that even thiscurrent of intermediate strength will not be sutlicient to cause anactuation of the full stop relay 25 The battery L is able to cause theflow of a current of sutficient strength to actuate all three of thesignal relays only when both resistances have been cut out of thesignaling circuits. When, therefore, the moving train reaches the blockD, a signaling circuit of very low re sistance will be provided in casethe controlling relay 13 is still deenergized due to the presence of acar or train in the block C. In such case the armatures of all three ofthe signal. relays will be attracted to cause the actuation of theirrespective signal lamps and bells. The engineer will, of course,understand the repeated actuation of the test lamp and bell to mean thatthe block signaling system is in perfect operation.

Any defect in the system will either cause the flow of a large currentwhen connection is made with the track contacts or will result in theflow of no current whatever. In the first case the engineerwill bringhis engine under control or to a full. stop, just as though there were atrain standing in an adjacent block. If, on the contrary he notes thefailure of the test signal upon the passage of the pairs of trackcontacts, he will understand that there is some defect in the signalingsystem and that it cannot be relied upon. He will in this case alsobring his train under control and proceed in such manner as to avoiddanger of collision or derailment. The engineer will understand alsothat in the normal operation of the system he will receive not only thetest signal but also a caution signal whenever he brings his train intoa position two blocks distant from a train moving or standing upon thesame track. He will, therefore, proceed with his train under controluntil. upon the passage of another set of track contacts, the absence ofthe caution signal indicates to him that the obstruction upon the secondblock in advance has been removed. In such event he may proceed again atfull speed. If, however, the caution signal continues to be displayedwhenever he passes a set of track contacts, he will continue to keep histrain under control, and it upon passing into the next block theactuation of the stop signal relay shows that there is a train or abreak of the rail in the next block in advance, he will bring his trainto a full stop before passing into the next succeeding block of track.

It will be unnecessary to explain in detail that when a single track isblocked in both directions, as indicated in Fig. 1, the signalingmechanism will be actuated to indicate the approach of another trainhead on, the signals in this case being actuated in the engine cabs ofboth trains. It will be understood furthermore than when one trainfollows another in either direction, the block signallng system Wlllserve to lndicate to the engineer of the second train whenever the firsttrain is less than three blocks in advance of the following train.

In order to make certain that the engineer will recognize and act inaccordance with the display of the caution and full stop signals, I haveshown in F 2 an auxiliary winding numbered 30 upon the cores of therelays 25 and 25 These auxiliary windings are respectively included incircuits containing normally closed spring switches numbered 31,armatures 32 and armature contacts 33. The auxiliary armatures 32 and 32are preferably adjusted so as to be attracted and released only when themain armatures of the same relays are attracted and released.

When, therefore, suflicient current flows through the signal relays toattract the armature 26, the auxiliary armature 32 will also beattracted to close a circuit through the auxiliary winding 30 and thenormally closed spring switch 31 Current flowing through. this auxiliarywinding will maintain the energization of the caution signal relay, evenafter the contacts G and H have broken circuit with the track contacts.The caution signal lamp and bell will continue, therefore, to beactuated until the engineer positively recognizes them and restores themto their normal condition by depressing the key 31 to open the circuitof the auxiliary winding 30 whereupon both armatures of the cautionsignal relay will be released and restored to their normal position,thereby opening the local circuit of the caution signal lamp and bell.In like manner the at traction of the armature 26 clue to the [low of aheavy current through the relay 25 will cause the closure of the circuitthrough the auxiliary winding 30 the flow of current through thiscircuit being maintained until the engineer recognizes the stop signaland depresses the spring switch 31 to open the circuit of the auxiliarywinding of the full stop signal relay. This auxiliary equipment of thecaution and full stop signal relays transforms them into what may betermed locking relays which upon actuation continue to act untilunlocked and thus restored to their normal condition by the actuation ofthe associated buttons or switches. By virtue of this equipment therecan be no excuse for the failure of an engineer to understand andappreciate the signals provided for the safe conduct of his train.

In order to test the engine equipment, I preferably provide a testingcircuit which may be operated by the engineer before commencing a run orat any other time when he finds it desirable so to do. This testingcircuit consists essentially of a resistance varying device connectedwith the moving contacts G and H. This is shown in Fig. 2 in the form ofacircuit leading to a switch arm 32. This switch arm may be swung into aposition to make electrical connection with any one of the contacts 33,34 or 35. The resistance 36 connected between the contact 33 and themoving contact G is equal to the normal resistance of the signalingcircuits previously traced on Fig. 1- The resistance 3'? is equal tothat of the signaling circuit in which the resistance 22 has been cutout by the denergization of the controlling relay. The resistance of thewire 38 which leads from the contact 35 is equal to that of thesignaling circuit in which both of the resistances have been cut out.The resistance of this circuit is practically negligible, for when bothof the resistances are cut out, the circuit is practicallyshort-circuited.

In order to test the condition of the signaling devices 28 and 29, thesignal relays 25", 25 and 25 and the circuits local to the engine cab,the engineer swings the switch arm 32 successively into connection withthe contacts 33, 34 and 35. When the switch arm makes connection withthe contact 33, current will flow in the cab circuit in the same mannerand with the same strength as it would when the moving contacts makeconnection with a pair of track contacts which form the terminals of asignaling circuit in its normal high resistance condition. Under thesecircumstances the apparatus should be actuated to cause the operation ofthe test signal alone. hen the switch arm 32 is brought into connectionwith the contact 34, both the test and caution signals should bedisplayed. \Vhen the switch arm 32 is brought into connection withcontact 35, all of the signaling devices should be actuated in the samemanner as when the engineer receives the full stop signal when runningupon the road. If for any reason the signaling" devices do not operatein this manner when tested by means of this auxiliary test circuit, theengineer will be apprised of the fact that something is wrong, and thedefect may be located and remedied.

In Figs. 5 and 6 I have illustrated in some detail the preferred form ofthe track contacts already referred to. These contacts take the form ofbrushes of steel bristles 4O embedded in a suitable back 41. The sinaling circuits previously described terminate in the bristles of thesebrushes. Above each brush is mounted a protecting board or cover 42, andrubber cloth or other suitable flexible material is fastened around theedges of the cover 42 so as to protect the steel brush from rain, sleetor snow- The rubber cloth is, however, flexible, so that when theprojecting contact rails attached to the locomotive tender approach thebrush, the rubber cloth will be deflected, as indicated in dotted linesin Fig. 6, to permit the passage of the contact bar G or H as the casemay be. After the passage of the contact bars, the rubber cloth willspring back into its normal position, as shown in the full lines. InFig. 5 I have indicated the I-beam frame of a locomotive tender indotted lines at 44. So also I have indicated in dotted lines the contactbars G and H in the posi tlon which they assume while passing undertrack contact brushes 40. The brush con tacts are suitably insulated at45 from the fork-shaped support 46. This support is riveted or otherwiseattached to an iron post 47, this post being simply a piece of pipe, tothe upper end of which a cap 48 is screwed and the lower end of which isscrewed into a suitable base plate 49, this plate being bolted in turnto a pair of extended railroad ties 50, 50. This manner of constructingthe contact-making devices may be reversed by attaching the elongatedsteel brushes to the sides of the locomotive tender while suitable postsalong the right of way support contact bars like those which I haveshown upon the locomotive tender. In either case the flexibility of thebristles of the brushes will permit considerable sidewise movement ordisplacement and still in sure the making of good electrical connection.

In Fig. 3 I have illustrated a modification of the track circuit whichis particularly well adapted for use upon tracks which are laid in dampground or where the ballast is such as to retain considerable moisturewith the attendant danger of short-circuiting the two rails of thetrack. In Fig. 3 I have shown a single block of a railway in which,however, each of the rails is frequently divided by insulating joints I.Each of the insulated sections of the block is provided. with a trackcircuit comprising a battery 11 and a track relay 60. I have shown at153* a controlling relay having functions corresponding with those ofthe controlling relays shown in Fig. 1, this controlling relay beingprovided with an energizing circuit leading from the battery 62 throughthe winding of the relay 13*. The current flowing in this circuit servesnormally to energize the relay 13*, but whenever any one of the sectionsof the block shown in Fig. 3 is shortcircuited, the associated trackrelay 60 will be deenergized, thereby permitting the retraction of itsarmature to open the circuit which leads from the winding of thecontrolling relay 18 to the battery 62. Upon deenergization, therefore,of any one of the track relays, there will be a correspondingdenergization of the controlling relay 13 for the same block. Theoperation of the system will, therefore, correspond with that previouslyexplained in connection with Fig. 1. The advantage of this arrangementin certain cases will be apparent to those skilled in the art. Sinceeach of the insulated sec tions of a given block is comparatively short,there will be little opportunity for leakage of current from one rail toanother and by the use of a low voltage battery, it will be easilypossible to control satisfactorily the operation of the track relays. Bythe use of this arrangement, the lengths of the blocks as determined forsignaling purposes, will not be limited by the distance through which itwill be possible sufiiciently to insulate the rails from one another.

It will be apparent that many modifications of my invention may be madewithout departing from the spirit thereof, and I do not, therefore, wishto be limited to the precise disclosure herein contained. The scope ofwhat I claim as my invention is indicated solely in the following claimsfor which I desire to secure Letters Patent:

1. In a railroad block signaling system, the combination with a seriesof blocks, of a controlling relay for each block, a normally closedtrack circuit in which each controlling relay is connected, a source ofcurrent in said track circuit whereby the electrical connection of thetwo rails of a block causes the deenergization of the associatedcontrolling relay, suitable track contacts placed in each block, asignaling circuit extending from each controlling relay to the trackcontacts in the second block in each direction, two resistances normallyincluded in each signaling circuit, switch mechanism adapted to cut oneof the resistances out of the signaling circuit upon thedeiinergizationof the controlling relay, switch mechanism adapted toshort circuit the signaling circuit terminating in the next block ineach direction upon the deenergization of the associated controllingrelay, three signal relays carried by a locomotive, said signal relaysbeing differentially adjusted, each to respond to currents of differentstrength, a source of current carried by the locomotive, said relays andsaid source of current being connected in a circuit terminating inmoving contacts adapted to register and make electrical connection withthe track contacts, a local sig nal circuit for each of said signalrelays, an electric signaling device in each of said local circuits, asupplemental winding on one or more signal relays, each winding beingincluded in circuit with a pair of normally open switch contactscontrolled by the associated relay and adapted to be closed upon theenergization thereof to maintain the attraction of the relay armature,and a normally closed manual switch in circuit with the supplementalwinding or windings.

2. In a railway block signaling system, the combination with a series ofblocks, of a controlling relay for each block, a normally closed trackcircuit in which said con trolling relay is connected, a source ofcurrent in said track circuit whereby the electrical connection of thetwo rails of a block causes the denergization of the associated vcontrolling relay, a signaling circuit extending from each controllingrelay to the track contacts in the second block in each direction, tworesistances normally included in each signaling circuit, swlitchmechanism adapted to cut one of the resistances out of the signalingcircuit upon the deenergization of the controlling relay, switchmechanism adapted to short-circuit the signaling circuit terminating inthe next block in each direction upon the denergization of theassociated controlling relay, and a source of current and suitabledifferentially responsive signaling mechanism carried on a moving trainand adapted to make electrical connection with said track contacts.

3. In a railroad block signaling system, the combination with a seriesof blocks, of a controlling relay for each block, a normally closedtrack circuit in which each controlling relay is connected, a source ofcurrent in said track circuit whereby the electrical connection of thetwo rails of a block causes the deenergization of the associatedcontrolling relay, suitable track contacts placed in each block, asignaling circuit extending from each controlling relay to the trackcontacts in the second block to the rear, two resistances normallyincluded in each signaling circuit, swjitch mechanism adapted to cut oneof the resistances out of the signaling circuit upon the deenergizationof the controlling relay, switch mechanism adapted to short circuit thesignaling circuit terminating in the next block to the rear upon thedeenergization of the associated controlling relay, three signal relayscarried by a locomotive, said signal relays being differentiallyadjusted, each to respondto currents of different strength, a source ofcurrent carried by the locomotive, said relays and said source ofcurrent being connected in a circuit terminating in moving contactsadapted to register and make electrical connection with the trackcontacts, a local signal circuit for each of said signal relays, anelectric signaling device in each of said local circuits, a supplementalwinding on one or more signal relays, each winding being included incircuit with a pair of normally open switch contacts controlled by theassociated relay and adapted to be closed upon the energization thereofto maintain the attraction of the relay armature, and a normally closedmanual switch in circuit with the supplemental winding or windings.

4. In a railway block signaling system, the combination with a series ofblocks, of a controlling relay for each block, a normally closed trackcircuit in which said controlling relay is connected, a source ofcurrent in said track circuit whereby the electrical connection of thetwo rails of a block causes the deenergization of the associatedcontrolling ielay, a signaling circuit extending from each controllingrelay to the track contacts in the second block to the rear, tworesistances normally included in each signaling circuit, switchmechanism adapted to cut one of the resistances out of the signalingcircuit upon the deenergization of the controlling relay, switchmechanism adapted to short-circuit the signaling circuit terminating inthe next block to the rear upon the deenergization of the associatedcontrolling relay, and source of current and suitable dili'erentiallyresponsive signaling mechanism carried on a moving train and adapted tomake electrical connection ith said track contacts.

5. In a rail 'ay block signaling system, the combination with a seriesof blocks, of a controlling relay for each block, a normally closedtrack circuit in which said controlling relay is connected, a source ofcurrent in said track circuit whereby the breaking of a ail orshort-circuiting of the two rails of a block will cause thedeenergization of the associated controlling relay, a signaling circuitextending from each controlling relay to suitable terminals in thesecond block to the rear, two resistances normally included in eachsignaling circuit, switch mechanism operated by each controlling relayto cut one of the resistances out of the associated signaling circuit,switch mechanism operated y each controlling relay to cut the otherresistance out of the signaling circuit ter minating in the next blockto the rear, and suitable electrical signaling crevices differ entiallyresponsive to currents of different strength and adapted for connectionwith the terminals of the signaling circuits.

6. In a railway block signaling system, the combination with a se-ies ofblocks, a signaling circuit extending from each block to the secondblock in each direction, a resistance normally included in eachsignaling circuit, suitable mechanism controlled in its operation by thecondition of or upon the track which constitutes the associated blockand adapted upon actuation to reduce the resistance of the signalingcircuits extending from the associated block and terminating in thesecond block in each direction and to reduce still further theresistance of the signaling circuits terminating in the next adjacentblock in each direction, and electrical signaling devices adapted forconnec tion with the terminals of the signaling circuits.

7. In a railway block signaling system, the combination with a series ofblocks, a signaling circuit extending from each block to the secondblock in each direction, a resistance normally included in eachsignaling circuit, suitable mechanism controlled in its operation by thecondition of or upon the track which constitutes the associated blockand adapted upon actuation to reduce the resistance of the signalingcircuits extending from the associated block and terminating in thesecond block in each direction and to reduce still further theresistance or" the naling circuits terminating in the next adjacentblock 11] each direct1on, a plurality of signal relays differentiallyresponsive to currents of diiterent strength, and a source of currenthaving a circuit adapted for connection with the terminals of saidsignaling circuits, and electrical signaling devices connected in localcircuits controlled by the signal relays.

8. In a railway block signaling system, the combination with a series ofblocks, a signaling circuit extending from each block to the secondblock in each direction, a resistance normally included in eachsignaling circuit, suitable mechanism controlled in its operation by thecondition of or upon the track which constitutes the associated blockand adapted upon actuation to reduce the resistance of the signalingcircuits extending from the associated block and terminating in thesecond block in each direction and to reduce still further theresistance of the signaling circuits terminating in the next adjacentblock in each direction, a plurality of signal relays diiterentiallyresponsive to currents of different strength, and a source of currenthaving a circuit adapted for connection with the terminals of saidsignaling circuits, electrical signaling devices connected in localcircuits controlled by the signal relays, and a supplemental winding oncertain of the signal relays, each supplen'iental winding being includedin a local circuit containing normally open switch contacts controlledby the associated relay and a normally closed manual switch.

9. In an electric signaling system, the combination with three signalrelays having main windings serially connected in circuit, said relaysbeing differentially adjusted to respond to currents of differentstrengths, a supplemental winding for the relays responding to currentof intermediate strength, and a supplen'iental winding for the relayresponding to current of maximum strength, a local circuit for each ofsaid supplemental windings, each local circuit including a normallyclosed, manual switch and normally open switch contacts controlled bythe associated relay, and suitable signal devices controlled by each ofthe three relays.

10. In a track contact for a cab signaling system, the combination witha brush having depending metal bristles, of a cover for said brush,suitable flexible material attached to said cover and extendingdownwardly to protect the sides of said brush as and for the purposedescribed.

11. In a track signaling system, the combination with a supporting post,of a forklike bracket attached thereto, a pair of con tacts comprisingbrushes with depending bristles supported by and insulated from thefork-like bracket, acover for each of the brushes, and a curtain ofrubber cloth attached to each of the covers and extending downwardlyaround the sides of the brushes to protect them from the weather, as andfor the purpose described.

12. In a railway block signaling system, the combination with a seriesof blocks comprising a pair of rails insulated from the rails of thenext succeeding block, a track circuit including a controlling relayassociated with each block, track contacts located in each block, acommon return conductor, a signaling circuit including the commonconductor and extending from each cont-rolling relay to the trackcontacts of the second block in each direction, switching mechanismserving upon the actuation of each controlling relay to reduce theresistance of the signaling circuits terminating in the track contactsof the second block in each direction and serving also to reduce stillfurther the resistance of the signaling circuits terminating in the nextadjacent block in each direction, and electrically operated signalingmechanism adapted for connection with the track contacts.

13. In a railway block signaling system, the combination with a seriesof blocks comprising a pair of rails insulated from the rails of thenext succeeding block, a track circuit including a controlling relayassociated with each block, a common return conductor, a signalingcircuit including the common conductor and extending from eachcontrolling relay to the track contacts of the second block to the rear,switching mechanism serving upon the actuation of each controlling relayto reduce the resistance of the signaling circuit terminating in thetrack contacts of the second block to the rear and serving also toreduce still further the resistance of the signaling circuit terminatingin the next adjacent block to the rear, and electrically operatedsignaling mechanism adapted for connection with the track contacts.

14. In a railway block signaling system, the combination with a seriesof blocks, of two signal controlling devices, each in a separate block,and two signal conveying paths, each path being adapted to conveysignals to a different block, the actuation of the first signalcontrolling device serving to reduce the'resistance in the first of saidpaths and to reduce still further the resistance of the second of saidpaths and the actuation of the second signal controlling device servingto establish a similar low resistance condition in the first of saidpaths.

15. In a railway block signaling system, the combination with acontrolling relay and a circuit therefor, a plurality of insulatedsections comprising the rails which constitute a single block, a trackrelay and circuit for each of the insulated sections, and means wherebythe operation of any of the track relays Will operate the controllingrelay, such controlling relay adapted by its operation to change theresistance of a signaling circuit associated With said block, saidsignaling circuit being closed and of difierent resistance for eachsignaling condition.

16. In an electric signaling system, the combination With a plurality ofsignal relays connected in a common circuit, said relays beingdifferentially adjusted to respond to currents of different strength asignaling circuit adapted for connection with the circuit in Which saidsignal relays are connected, means for changing the resistance of thesignaling circuit to effect the differential actuation of the signalrelays, an auxiliary test circuit connected with the terminals of thecommon circuit through the signal relays, and means for varying theresistance of the auxiliary test circuit to correspond With the normalvariations in the resistance of the signaling circuit as and for thepurpose described.

17. In a railway block signaling system, the combination with a seriesof blocks, of a signaling circuit extending from each block in eachdirection, a resistance normally included in each signaling circuit,mechanism controlled in its operation by the condition of or upon thetrack of such block, such mechanism adapted by its actuation to vary theresistance of the signaling circuits extending from such block, andelectrical signaling devices adapted for connection With the terminalsof the signaling circuits.

In Witness whereof, I hereunto subscribe my name this 5th day of AprilA. D., 1907.

HARRY M. COULTER.

WVitnesses:

LYNN A. WILLIAMS, FRED WV. KoEHN.

